# gst: vorticity-induced surfing and trapping in porous media

<< Microorganisms often encounter strong confinement and complex hydrodynamic flows while navigating their habitats. Combining finite-element methods and stochastic simulations, (AA) study the interplay of active transport and heterogeneous flows in dense porous channels. (They) find that swimming always slows down the traversal of agents across the channel, giving rise to robust power-law tails of their exit-time distributions. These exit-time distributions collapse onto a universal master curve with a scaling exponent of ≈ 3/2 across a wide range of packing fractions and motility parameters, which can be rationalized by a scaling relation. >> 

<< ️(AA) further identify a new motility pattern where agents alternate between surfing along fast streams and extended trapping phases, the latter determining the power-law exponent. Unexpectedly, trapping occurs in the flow backbone itself -- not only at obstacle boundaries -- due to vorticity-induced reorientation in the highly-heterogeneous fluid environment. >>

Pallabi Das, Mirko Residori, Axel Voigt, et al. Vorticity-induced surfing and trapping in porous media. arXiv: 2511.02471v1 [cond-mat.soft]. Nov 4, 2025.

https://arxiv.org/abs/2511.02471

Also: swim, microswimmers, intermittency, disorder, vortex, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, swim, microswimmers, intermittency, disorder, vortex, self-propel, run-and-tumble dynamics, hop-and-trap pattern, surf-and-trap motility pattern.

# gst: implementation of a generalized intermittency scenario in the Rossler dynamical system.

<< The realization of novel scenario involving transitions between different types of chaotic attractors is investigated for the Rossler system. Characteristic features indicative of the presence of generalized intermittency scenario in this system are identified. The properties of "chaos-chaos" transitions following the generalized intermittency scenario are analyzed in detail based on phase-parametric characteristics, Lyapunov characteristic exponents, phase portraits, and Poincare sections. >>

O.O. Horchakov, A.Yu. Shvets. Implementation of a generalized intermittency scenario in the Rossler dynamical system. arXiv: 2511.03364v1 [nlin.CD]. Nov 5, 2025.

https://arxiv.org/abs/2511.03364

Also: intermittency, attractor, chaos, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, intermittency, attractors, chaos, transitions, chaos-chaos transitions.

# gst: experimental observation of hidden multistability in nonlinear systems.

<< ️Multistability, the coexistence of multiple stable states, is a cornerstone of nonlinear dynamical systems, governing their equilibrium, tunability, and emergent complexity. Recently, the concept of hidden multistability, where certain stable states evade detection via conventional continuous parameter sweeping, has garnered increasing attention due to its elusive nature and promising applications.  >>

<< ️In this Letter, (AA) present the first experimental observation of hidden multistability using a programmable acoustic coupled-cavity platform that integrates competing self-focusing and self-defocusing Kerr nonlinearities. Beyond established bistability, (They) demonstrate semi- and fully-hidden tristabilities by precisely programming system parameters. Crucially, the hidden stable states, typically inaccessible via the traditional protocol, are unambiguously revealed and dynamically controlled through pulsed excitation, enabling flexible transitions between distinct types of stable states. >>

Kun Zhang, Qicheng Zhang, Shuaishuai Tong, et al. Experimental Observation of Hidden Multistability in Nonlinear Systems. arXiv: 2511.04150v1 [nlin.CD]. Nov 6, 2025.

https://arxiv.org/abs/2511.04150

Also: instability, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, stability, multistability, hidden multistability, semi- fully-hidden tristabilities, pulsed excitation.

# gst: energy transport and chaos in a one-dimensional disordered nonlinear stub lattice

<< ️(AA) investigate energy propagation in a one-dimensional stub lattice in the presence of both disorder and nonlinearity. In the periodic case, the stub lattice hosts two dispersive bands separated by a flat band; however, (They) show that sufficiently strong disorder fills all intermediate band gaps. By mapping the two-dimensional parameter space of disorder and nonlinearity, (AA) identify three distinct dynamical regimes (weak chaos, strong chaos, and self-trapping) through numerical simulations of initially localized wave packets. >>

<< ️When disorder is strong enough to close the frequency gaps, the results closely resemble those obtained in the one-dimensional disordered discrete nonlinear Schrödinger equation and Klein-Gordon lattice model. In particular, subdiffusive spreading is observed in both the weak and strong chaos regimes, with the second moment m_2 of the norm distribution scaling as m_2 ∝ t^0.33 and m_2 ∝ t^0.5, respectively. The system’s chaotic behavior follows a similar trend, with the finite-time maximum Lyapunov exponent Λ decaying as Λ ∝ t^−0.25 and Λ ∝ t^−0.3. For moderate disorder strengths, i.e., near the point of gap closing, (They) find that the presence of small frequency gaps does not exert any noticeable influence on the spreading behavior. >>

<< ️(AA) findings extend the characterization of nonlinear disordered lattices in both weak and strong chaos regimes to other network geometries, such as the stub lattice, which serves as a representative flat-band system. >>

Su Ho Cheong, Arnold Ngapasare, et al. Energy transport and chaos in a one-dimensional disordered nonlinear stub lattice. arXiv: 2511.04159v1 [nlin.CD].  Nov 6, 2025.

https://arxiv.org/abs/2511.04159

Also: network, waves, disorder, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, networks, waves, disorder, chaos, stub lattice, subdiffusive spreading.

# gst: dynamical phase transitions across slow and fast regimes in a two-tone driven Duffing resonator

<< In this work, (AA) established an analytical framework to describe dynamical phase transitions in a Duffing resonator under bichromatic driving. (They) reveal two regimes: a slow-beating one, where the secondary tone slowly modulates the main drive and can push the system past bifurcations, and a fast-modulation one. >>

<< (AA) analysis shows that even a weak secondary tone can profoundly reshape the dynamics, inducing transitions between coexisting attractors that cannot be explained by perturbative treatments of the secondary tone. >>

<< This provides a qualitative yet predictive tool to detect and categorize different types of dynamical phase transitions in two-tone driven nonlinear systems. >>

Soumya S. Kumar, Javier del Pino, et al. Dynamical Phase Transitions Across Slow and Fast Regimes in a Two-Tone Driven Duffing Resonator. arXiv: 2511.01985v1 [cond-mat.mes-hall]. Nov 3, 2025.

https://arxiv.org/abs/2511.01985

 

Also: attractor, transition, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, attractor, transitions, chaos,  Duffing resonator, bichromatic driving. 

# gst: apropos of shape transitions, midveins regulate the shape formation of drying leaves.

<< ️Dried leaves in nature often exhibit curled and crumpled morphologies, typically attributed to internal strain gradients that produce dome-like shapes. However, the origin of these strain gradients remains poorly understood. Although leaf veins--particularly the midvein--have been suggested to influence shape formation, their mechanical role has not been systematically investigated. >>

<< ️Here, (AA) demonstrate that mechanical constraints imposed by the midvein play a crucial role in generating the diverse morphologies that emerge during leaf drying. Combining numerical simulations and theoretical analysis, (They) show that a uniformly shrinking leaf lamina constrained by a non-shrinking midvein gives rise to two distinct types of configurations: curling-dominated and folding-dominated morphologies. In the curling-dominated regime, both S-curled and C-curled shapes emerge, with C-curled configurations more commonly observed due to their lower elastic energy. In contrast, the folding-dominated regime features folding accompanied by edge waviness. Theoretical modeling reveals a linear relationship between midvein curvature and mismatch strain, consistent with simulation results. >>

<< ️Moreover, (AA) find that the morphological outcome is governed by the ratio of bending stiffnesses between the lamina and the midvein. (They) construct a comprehensive phase diagram for the transitions between different configurations. These findings provide a mechanical framework for understanding shape formation in drying leaves, offering new insights into natural morphing processes and informing the design of bio-inspired morphable structures. >>

Kexin Guo, Yafei Zhang, et al. Midveins regulate the shape formation of drying leaves. arXiv: 2507.01813v1 [cond-mat.soft]. Jul 2, 2025.

https://arxiv.org/abs/2507.01813

Also: waves, transition,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, transition, leaf drying, curled and crumpled morphologies, internal strain gradients, dome-like shapes, curling-dominated and folding-dominated morphologies, edge waviness, midvein curvature and mismatch strain, life.

# life: apropos of immigration problems, 'China is going to win the AI race', by Jensen.

<< ️"As I have long said, China is nanoseconds behind America in AI," Nvidia CEO Jensen Huang said in a statement posted on X late on Wednesday. >>

<< ️"A policy that causes America to lose half of the world's AI developers is not beneficial in the long term, it hurts us more," >>

Nvidia's Jensen Huang: 'China is going to win the AI race,' FT reports. Reuters. Nov 6, 2025.

https://www.reuters.com/world/asia-pacific/nvidias-jensen-huang-says-china-will-win-ai-race-with-us-ft-reports-2025-11-05/  Nvidia’s Jensen Huang says China ‘will win’ AI race with US.  https://www.ft.com/content/53295276-ba8d-4ec2-b0de-081e73b3ba43 

Also: life, ai (artificial intell) (bot), in https://www.inkgmr.net/kwrds.html 

Keywords: life, aibot, artificial intelligence.